1. Field of the Invention
The present invention relates to a thin-film transistor formed on a semiconductor thin film which is deposited on an insulating substrate and is crystallized in a predetermined direction, and to an electronic device and a display device which are fabricated by using the thin-film transistors. In particular, the invention relates to an electronic device and a display device, which employ thin-film transistors having channel regions formed in regions that are crystal-grown in a lateral direction, and which are suitably applied to analog circuits which perform signal processing of 1 GHz or more.
2. Description of the Related Art
As a display device of, e.g. OA equipment, which displays image information and text information, there is known an active-matrix flat-panel display which uses thin-film transistors. In recent years, with the development of multimedia communication technology, attention has been paid to an integrated-function type display as a next-generation display, which is called a “system-on-panel” display. This integrated-function type display is designed for personal use, has a small size and light weight, and has a high resolution and a high image quality. Moreover, peripheral functions relating to image display, such as driver circuits, memory circuits, DA converters and image processing circuits, are integrated on a display panel.
In the structure of a conventional display device, for example, in the case of a desktop computer, a system device and a display device need to be connected by a dedicated shield cable to which an unwanted radiation (electromagnetic interference) measure is applied. Alternatively, in the case of a notebook computer, a display and a system are integrated and are connected by a short flexible cable. In other words, in the prior art, the transmission path between the system and the display is designed as a path having a sufficient transmission speed for transmitting image data that is to be displayed. Thus, in order to cause a display to display an image, there is no choice but to dispose the system device in the vicinity of the display.
However, the conventional display device is not suited to the ubiquitous society which is expected to come in the future and realize “anytime, anywhere” networking.
As regards an electronic device, such as a mobile phone, which needs to be reduced in size, there is a problem that the mounting of components in the device is restricted by a flexible cable that is connected to the display.